Gun recoil spring bearing on barrel and breech block



J. B. J EWETT Nov. 3, 1959 Filed May 28. 1954 mTu I ii. i! Em igmgxkhan-l III- &

ll|l H 2 9 INVENTOR. JOHN BROWN JEWETT.

" %M 14 7" TOR/YE United States Patent GUN RECOIL SPRING BEARING ONBARREL AND BREECH BLOCK John B. Jewett, Newtown, Ohio, assignor toSportarms ,Mnnufacturing and Development Corporation, New- 2 Claims.(Cl. 89 -196) This invention relates to improvements in firearms of theself-loading type, either semi-automatic or fullautomatic andparticularly to the group having the so called blow back arrangement ofbreech mechanism in which the breech block retards the expulsion of afired cartridge case from the chamber by its inertia and the load in arecoil or breech return spring or springs.

The object of my invention is to provide a firearm of extreme mechanicalsimplicity without a locked breech but which will be capable of firingpowerful cartridges which usually necessitate a locked breech mechanismin which the breech block is locked to the barrel during the period ofdischarging a cartridge.

A further object is to provide a limited rearward movement of the barrelupon discharge of the cartridge.

A further object is to provide means for returning the barrel to normalposition.

A further object is to provide a blow back autoloading firearm in whicha minimum of risk is encountered by the shooter in firing faultyammunition.

My invention will be further readily understood from the followingdescription and claims, and from the drawings, in which latter:

Fig. l is a plan view of my improved firearm.

Fig. 2 is a side view of the same, partly in section.

Fig. 3 is an end view of the same.

Fig. 4 is a detailed perspective view of the end of the breech block,showing the extractors.

Fig. 5 is a detailed perspective view of the rear end of the barrel.

Fig. 6 is a detailed cross-section; taken in the plane of the line 6-6of Fig. 2.

Fig. 7 is a diagrammatic view to show the principle of the invention.

My improved firearm comprises the usual frame 11 having a forwardextending breech block guide 12 which is in the form of a U and engagingthe lower portion 13 of the barrel 14 by means of inwardly extendinglugs 15 received in grooves 16 in the lower portion 13 of the barrel.

The breech block 17 has extending side members 18 forming a forwardjournal 19 for the end of the barrel 14. This journal is tapered topermit easy disassembly of the barrel from the breech block.

The rear end of the barrel is provided with a cartridge chamber 20having a chamfer 21 for easy feeding of the cartridges 22 into thechamber.

The lower portion 13 of the barrel is normally spaced from the frame bymeans of springs 23 received in apertures 24 in the frame and bearingagainst pins 25 which contact the lower portion of the barrel. Therecoil spring 26 is mounted on a rod 27 which is threaded into thereceiver and provided with a shoulder 28 to permit the barrel to bespaced from the frame. A washer 29 bearing against a shoulder 30 engagesone end of 2 the recoil spring while the other end of the recoil springbears against the forward journal 19 of the breech block.

Assuming that a cartridge is in the chamber of the barrel and thetrigger 31 has been pulled, tripping the firing mechanism anddischarging the cartridge causing the bullet to be upset in the riflingand start out the barrel. It will be noted that the means of retainingthe barrel is the shoulder 28 which accepts the forward thrust of theupsetting bullet, and that the barrel return springs 23 positions thebarrel against this shoulder and that the recoil spring has in turnpositioned the breech block against the rear aspect of the barrel.

As the bullet travels out of the barrel, the cartridge case starts tomove backward in the chamber. The chamber pressure rises to a pointwhere the cartridge case grips the chamber walls to or nearly to thepoint of seizing. This occurs after the bullet has started out of thebarrel and the upsetting force thereof is expended. At the same time thebreech block has received a slight rearward acceleration and thefriction of the cartridge case walls drag the barrel back against theload of the barrel return springs 23. While the rear face of thecartridge case is thrusting back against the inertia of the breechblock, the load of the recoil spring is also assisting the backwardmovement of the barrel as it is stronger than the barrel return springs.Thus it will be seen that the breech block and barrel move backwardtogether due to the drag of the cartridge case on the walls of thecartridge chamber during the period of peak chamber pressure until thebarrel is finally arrested by the barrel meeting the frame. As thebullet has left or nearly left the barrel, the chamber pressure dropsallowing the inertia of the breech block to continue withdrawal of thefired cartridge case from the chamber.

Feeding of another cartridge is accomplished by the forward movement ofthe breack block under the impulse of the loaded recoil springs as inconventional arrangements.

Having thus fully described my invention, what I claim as new and desireto secure by Letters Patent is:

1. In an auto loading firearm, the combination of a frame, an unlockedbarrel and breech block rearwardly movable under recoil relative to theframe, a recoil spring having a rear end movable with and pressingrearwardly against a forwardly disposed surface of said barrel and afore end pressing forwardly against a rearwardly disposed surface ofsaid breech block, said recoil spring reacting solely between saidbarrel and said breech block to establish closure of said breech blockand barrel, and a return spring having a rear end pressing rearwardlyagainst said frame and a fore end pressing forwardly against saidbarrel, said return spring reacting directly between said barrel andsaid frame to position said barrel, said breech block and said recoilspring at battery position.

2. In an autoloading firearm, the combination of a frame formed with aforwardly extending guide of generally U-shaped section, a breech blockhaving a frontal ring portion and a rear block portion, a barrelslidably mounted within said ring portion and having grooves slidablycomplementary to said guide, said barrel and frame being formed with afirst pair of opposing surfaces which are spaced when the barrel is inbattery position but limit the rearward travel of the barrel on recoil,the barrel surface of said pair being provided by depending stopportion, a bolt projecting freely thru said depending stop portion andsecured to said frame and formed with a shoulder for arresting forwardmoveguide portion forwardly and freely extending through the ringportion of said breech block, a barrel return spring between said firstpair of opposing surfaces and having its rear end pressingagainst saidframe and its front end pressing against said barrel, a washer securedsolely to said barrel in front of said step portion and formed with anaperture to receive said spring guide'portion, and a recoil springreacting solely between said frontal ring portion of the breech blockand said washer, said recoil spring being spirally mounted on saidspring guide portion so that the rear end of said recoil springismovable with said barrel and washer, said recoil spring ex erting alocking force between said barrel and said breech block and said returnspring reacting directly between said barrel and said frame to positionsaid barrel, said breech block and said recoil spring in batteryposition.

UNITED STATES PATENTS

